This is a phase II, multicenter, active controlled 1:1:1 randomized 4-week parallel group study with 3 treatment groups (HOE901(30); HOE901(80); and NPH-human insulin. Primary objectives include (1) investigating the safety and tolerability of HOE901(30) and HOE901(80) in comparison to NPH insulin in insulin-dependent diabetes mellitus (IDDM) patients; (2) selecting a formulation to be investigated in phase III clinical trials; and (3) comparing the efficacy of HOE901 and NPH with regard to fasting glucose in IDDM patients.